NAME

SYNOPSIS

DESCRIPTION

Runs a number of housekeeping tasks within the current repository,
such as compressing file revisions (to reduce disk space and increase
performance) and removing unreachable objects which may have been
created from prior invocations of git add.

Users are encouraged to run this task on a regular basis within
each repository to maintain good disk space utilization and good
operating performance.

Some git commands may automatically run git gc; see the --auto flag
below for details. If you know what you’re doing and all you want is to
disable this behavior permanently without further considerations, just do:

$ git config --global gc.auto 0

OPTIONS

--aggressive

Usually git gc runs very quickly while providing good disk
space utilization and performance. This option will cause
git gc to more aggressively optimize the repository at the expense
of taking much more time. The effects of this optimization are
persistent, so this option only needs to be used occasionally; every
few hundred changesets or so.

--auto

With this option, git gc checks whether any housekeeping is
required; if not, it exits without performing any work.
Some git commands run git gc --auto after performing
operations that could create many loose objects.

Housekeeping is required if there are too many loose objects or
too many packs in the repository. If the number of loose objects
exceeds the value of the gc.auto configuration variable, then
all loose objects are combined into a single pack using
git repack -d -l. Setting the value of gc.auto to 0
disables automatic packing of loose objects.

If the number of packs exceeds the value of gc.autoPackLimit,
then existing packs (except those marked with a .keep file)
are consolidated into a single pack by using the -A option of
git repack. Setting gc.autoPackLimit to 0 disables
automatic consolidation of packs.

--prune=<date>

Prune loose objects older than date (default is 2 weeks ago,
overridable by the config variable gc.pruneExpire).
--prune=all prunes loose objects regardless of their age (do
not use --prune=all unless you know exactly what you are doing.
Unless the repository is quiescent, you will lose newly created
objects that haven’t been anchored with the refs and end up
corrupting your repository). --prune is on by default.

--no-prune

Do not prune any loose objects.

--quiet

Suppress all progress reports.

--force

Force git gc to run even if there may be another git gc
instance running on this repository.

Configuration

The optional configuration variable gc.reflogExpire can be
set to indicate how long historical entries within each branch’s
reflog should remain available in this repository. The setting is
expressed as a length of time, for example 90 days or 3 months.
It defaults to 90 days.

The optional configuration variable gc.reflogExpireUnreachable
can be set to indicate how long historical reflog entries which
are not part of the current branch should remain available in
this repository. These types of entries are generally created as
a result of using git commit --amend or git rebase and are the
commits prior to the amend or rebase occurring. Since these changes
are not part of the current project most users will want to expire
them sooner. This option defaults to 30 days.

The above two configuration variables can be given to a pattern. For
example, this sets non-default expiry values only to remote-tracking
branches:

The optional configuration variable gc.rerereResolved indicates
how long records of conflicted merge you resolved earlier are
kept. This defaults to 60 days.

The optional configuration variable gc.rerereUnresolved indicates
how long records of conflicted merge you have not resolved are
kept. This defaults to 15 days.

The optional configuration variable gc.packRefs determines if
git gc runs git pack-refs. This can be set to "notbare" to enable
it within all non-bare repos or it can be set to a boolean value.
This defaults to true.

The optional configuration variable gc.aggressiveWindow controls how
much time is spent optimizing the delta compression of the objects in
the repository when the --aggressive option is specified. The larger
the value, the more time is spent optimizing the delta compression. See
the documentation for the --window' option in git-repack[1] for
more details. This defaults to 250.

The optional configuration variable gc.pruneExpire controls how old
the unreferenced loose objects have to be before they are pruned. The
default is "2 weeks ago".

Notes

git gc tries very hard to be safe about the garbage it collects. In
particular, it will keep not only objects referenced by your current set
of branches and tags, but also objects referenced by the index,
remote-tracking branches, refs saved by git filter-branch in
refs/original/, or reflogs (which may reference commits in branches
that were later amended or rewound).

If you are expecting some objects to be collected and they aren’t, check
all of those locations and decide whether it makes sense in your case to
remove those references.

HOOKS

The git gc --auto command will run the pre-auto-gc hook. See
githooks[5] for more information.